Operationality in inputting, displaying, outputting and processing information is a main factor to decide the utility value of a cellular telephone. Accordingly, cellular telephones with pointing devices have been developed in recent years. The pointing device is an input unit used for specifying the cursor position on the display to input characters or control the cellular telephone. It is required to improve the operationality or usability of the pointing device while aiming at smaller and lighter cellular telephones.
There is found an example of equipment having the pointing device in Japanese Patent Application laid open No. HEI9-134248, “Pointing input unit and electronic equipment provided with the same”. In accordance with the prior art, a tabular operation button is slidably supported on the equipment so that plural processing objects can be handled by manipulating the button with a finger. In other words, a user can operate the equipment without shifting the operating position of his/her finger widely since it is unnecessary to use plural operation keys and buttons. Thus, the enhancement of operationality and the miniaturization of equipment can be achieved.
Besides, Japanese Patent Application laid open No. HEI9-282091 discloses a pointing device, in which a user can easily operate operation buttons by his/her thumb that works smoothly with forefinger while controlling the pointer position by the forefinger of his/her dominant hand.
However, there are some problems in the application of the above-mentioned pointing device to cellular telephones. First, the conventional pointing device does not have a function for facilitating line scrolling and page scrolling which are highly used on cellular telephones to select an item from a list or the like. Second, the moving speed of the pointer is too fast for the small screen of a cellular telephone.